On Sun, 13 Jun 2010 13:36:53 -0700 (PDT), Richard Fry
wrote:


Mendenhall's paper shows "RF spectrum showing distortion products"
that are 30dB down.

Not near the resonant frequency of the output tuning/matching network.

Another subjective term. How near is near? All products that
Mendenhall shows in the illustration titled "RF spectrum showing
distortion products" are 30dB down and those distortion products fall
between modulation sidebands (unless you are speaking of doubling and
trippling of the carrier frequency).

Returning to the amplifier of his own design, in his classic WREK
engineering report [you seem shy of acknowledging your authority's
work here] submitted to the FCC. Now, when I say "of his own design,"
I mean by him personally, at the bench, using tools, assembling
components against his own schematic. He explicitly states:
"Distortion at 100% = 1%." At "frequency removed from carrier" from
-35dB to -73dB out to "600 Khz and beyond."
"Harmonic and spurious radiation" at least -70dB.
"Harmonic distortion" at 100% worst case 2.3%
"Plate efficiency of 70% to 80%"
"Total efficiency of 68%" [plate power in / RF power out]
operating Class C.

And of course his statement that sends minds reeling:

"It was thus necessary to determine the plate load impedance
= (Eb - Emin) / I1
~= Eb/ Idc
~= 1000 Ohms
[Not very far from Walt's determination of 1400 Ohms from his own
bench.]
"Since this was to be coupled into a Z output of 50 Ohms, a impedance
transformation of 20:1 was needed. This was accomplished by using a
voltage divider of two series capacitors to series tune the plate
circuit."

His EIMAC reference found in other, later published papers conform to
every detail in his engineering report to the FCC and in those same
later papers. In fact, they offer a multitude of operational
parameters for a variety of tubes at many power levels, across many
bands and classes of operation.

73's
Richard Clark, KB7QHC